I'm designing a device that needs a 3-axis accelerometer. I've prototyped it with a module but want something smaller. Basically I want low cost - around $1 in small quantities. It looks like the Kionix KX-122-1037 meets my needs but have not found many examples or reports of people using it. Anyone used that or similar Kionix Accs? Any other favorites that costs about a buck?

One thing I am concerned about is home assembly with a 2x2 LGA (looks like all the cheap Accs use that package now). I'll use a reflow oven and stencil so I think it will go OK but hope someone with experience can give me words of wisdom, things to watch out for, etc. Kionix does have a nice appnote on this that gives me some confidence http://kionixfs.kionix.com/en/document/TN008 PCB Design Guidelines for 2x2 LGA Accelerometers.pdf

I'm going to try to cut a stencil on my CNC mill. It will be a learning experience. I can always bail and have it made for me at the worst case.

 

To follow up on this.

I got the boards from AllPCB (whew, 4 days from order to delivery, $5.49 - I'm still stunned by this) and ICs from Mouser.

Used a syringe to put the solder paste on. Well, actually, the needle was way too big and the solder paste (Kessler) not that sticky. So, I put a very light coating of flux down and a blob of paste off the the side and used a needle to get the solder balls onto the 12 pads. Next time I'll wipe most of the flux off before hand. Used a stereo microscope at about 20X. It wasn't pretty but gave it a try in the toaster oven.

Happy to say it worked just fine. You can see on the microscope picture that there is a little flux left (after 3 washing in isopropyl) and a few stray solder blobs. Those capacitors are 1206s, that accelerometer is tiny!


This LA trace shows reading the X, Y and Z axis 16 bit values with SPI.


I haven't tested the interrupt pins so there could still be some errors but the important ones all seem to be working. Also, I need to try and make a stencil.

What's really great about this is now I can add an accelerometer to my projects for $1 and a tiny bit of PCB real estate.